Condenser.



densers, of whichvthe following is a specili-A UNITED sTATEs PATENT oEEioE.

I KUHLMANN, F BERLIN, G'EEIVLAIIY,I ASSIGNOR TO GENERAL ELECTRIC u COMPANY, A CORPORATION OF NEW YORK.

coNnENsEa.

Specification of Letters Patent.

Patented. Aug. 15,1911.

I Application filed April 29, 1910. Serial No. 558,489.

To all whom it mayconcem:

Be it known that I, KARL KUHLMANN, a' subject of' the Emperor of Germany, residing at Berlin, Germany,have invented certain new and useful Improvements lin Concation.-

' In hi h voltage condensers in which the #plates o opposite polarity are separated by a layer :of dielectric, it has been found that the dielectric stressv concentrates near the edges of the plates, while at the other points off ren between the plates the stress'is nearly uni ofthe concentration-of the stress condensers Y y made of glass, porcelain, or other materials and' constructed after lthe manner of Leyden' tjarsalmostv always break down at points which are not covered by the metallic coat- ,ing or plates and which are near the edges. 'oftheplates Attempts have been made lto prevent` this breakdown by vincreasing the thickness of the dielectric near the edges of theplates or at the' neck ot the condensers when they. are made in the form of j ars.- It has also been proposed to divide the dielectric lengthwise into'layers for the purpose ering the distribution of stress throughout the dielectric substantially uniforni, but owingy to the: diiiiculty of securing layers of dielectric ,of the same strength and thickness at all points, differences of potential develop between the different points on the layers and result in local currents which represent losses in the condenser and also cause heating. y'

The ob'ect of vmy. inyention is to prevent" the breaking down of the condenser near the edge of the plates and alsofto proyide a condenser i n which local currentsin the dielectric are prevented and which 'remainscool under normal operating conditions.

In carrying out my invention heating and puncturing of the dielectric is prevented' by reducing thecapacity of the edge ofthe di electric in any suitable way, preferably by dividing the dielectric into VVlayers or portions and bendingAthe layers apart so as to produce an airgap or recess in the end sur! faces of the dielectric. Local currents and heating in the dielectric are prevented by' means of a'rnejallic sheet mounted between the plates o f'thecondenser and insulated from them, and preferably so arranged that the 'ends of the metallicsheet project fer v w.

enough to be 'in contact with the air surrounding the condenser and to act as cooling surfaces to keep the temperature of the condenser within desirable limits. v l

My invention will best be understood inf connection with the accompanying drawings which showsome. of the numerous ways in which my invention may be embodied and in which- Figure 1 is a longitudinal section of a con-l denser of the usual type showing diagrammatically how the dielectric is perforated .near the edges lor the plates; Fig. 2 is a longitudinal section of one form of condenser embodying my invention; Fig. 3 is a longi-` tudinal section of a form of condenser embodying myvinvention and showing the dielectric divided lengthwise into two layers; Fig. 4 is a' longitudinal section of a condenser having two layers of dielectric separated by a metallic sheet; Fig. 5 is a longitudinal section fof a condenser similar to that shown in Fig. 4; withnthe ends of the metallic sheet extended to form cooling surfaces; and Fig. 6 is a longitudinal section of a form of condenser having numerous.. plates which may at will, by suitable ineans,.

be connected either in series or in parallel.

If a condenser, such as a Leyden jar, is connected to an electrical machine, there is observed at the moment the spark passes between the conductors of the machine a marked coruscation over the uncoated neck of the dielectric. Shortly before the spark passes between the conductors of the machine this coruscation is also present, but to a much smaller extent. If, in Fig. 1, we assume 4the individual andiopposed cylindrical surfaces Z1 and Z2 to be the terminal planes of the dielectric d, and@ the outside conducting layers of the cylindrical surface as the coatings of elementary Y condensers, ,the

charging and discharging of these elemen` tary condensers takes place from the edges of the metallic coatings i and a and that which is observed as a coruscation s is nothing more than a charging current which passes into the individual condenser elements. This current is, of course, strongest where it passes out of thecoating and decreases with the distance along the dielectric from the edge of the coating. At the moment when the spark passeslhetween the conductors of the electrical machine, the.f .condenser circuit discharges'at high frep, neeoiae quency and since the` charging currentlof accordance-width my each condenser is highei` in vprepoitiony to tiene are @vermine i frequency, vthe coruscaticn will be much tliekdierent. layers of me ei e, nietah. greater at the passage of the sparklin aclic Sheet `in the rnenneif shown diegrsiib cordance with the explanation above inside; matically inllig. 4r, in which the metalli@ The eoiusention, however, heats the dielecsheet 7, is embedded in a. dielectric' between tric :it the edges and on account 0f the poor the plates of the condenser :md is insulated heilt COIIClHCVlty 0f all dielectrics the heet from the plates. in order te maintain the is distribute-d very slowly, with the result' temperature oit condenser Within dethat e. great local increase of temperature sirulile 'limits tl ieellie sheets prefer- 'occurs in 'the dielectric, which is therefore ably hay@ hei C A f Y tended, Slm'wu readily broken down at. the edges where the in Fig. sa. maus Zi nyejeei inte coruscation is greutest. i the recesses in the "'l' c'iirie and The danger of the dielectric being pene-- .re exposed'to tured at the edge oi 'the coating is Very denser, Wliei'ebj greatly decreased in the form of invention condenser is embodied in Fig. by reducing the eapeeity Sheets I, md il.; at the by, i `liijig the dieleetzie in the sheets. the middle and' bending thet tivo ,portions My invention :Liso provi@ :i Condenser pm-", Pl'efe'l-bly in 5ml! Ll W2k? that one of comprising e, plurality ilates which may the port-ions has :i curvature of i relatively be. at will, cnneeted n 3 emile/ @1j-- great lidiUS. .AS .iS evident, YOIH Fig., 2, in series land one 'ferm of 'my .nventien ie' the divergii'ig .poltns oit the dielectric. .shown in G, in Wh h the intermedietel which PQlllCi beynfl .llle'edges ll wie? plates c5 sre'previded w i pro-je ne ends plate a :ind of .the inner plate if have between, similar te the metall ii, and hemnnii; Orylecess which isdn effect' .by any suitable f; mi m. the II'OflHCGdlWllWQOH lll@ llll .plmUS 0f outer, intermediulel i inner nim" nin);- l'll@ ClCmGllHfy @.ODQUSGTSQ-21!1d.Z2,Wl1Cll, be'conneel'ed either series GV in ggfuallel, of course, are not present "in the ccndensers as desired. HS ILCIHIllQV,Ollillltfli .blli HY@ indiflteil My invention insyhe'einheit only for the purpose et illustrutinmir the prinother'. fgrms than tl profils@ ciple ot my inwntion. Sinee'gtliedielectric shown. and l' "we fio not iiin... my Constant oit' ui); is coiieirifnbljy' smaller than inventim {anemie} g yimg gnmlil'mthm" et' tlleeolil clielel;I ri@ generally used., tions hereofwl'i sui; e ,memseives mtime the ezipzieity uf' the Clflllentilly CODdGHSCS ,skilled in the art Withuutdeparting from Z" und Z2 quite considerablyreduced,and the spirit of my Even-ifm? f 13.3 @E in censequem-e the amountot'. eoruseation, which is set forth in lthe :um: d cl ins. and therefore the liabilitjyT et. lii'enkdoyvn atn lVhat claim es new und desire to secure points on the.. neuh: of ,plOjCtil'lg POIOII O by Letters vPatent 0f the Untell States. is,--- the dielectric is'edued. v Any other dierleel, A condenser comprising 1. .indisch-ic tric WlllCll iiilhlidv@ substantially the Same having its end dividedinte livei'ging por# properties us aii muy he introduced into the tions. i gap or recess between the diyerging p01. Quei condenser yem'nprisin udielectrie tions of the dielectric so long; us the capacity v tft-ving iig gni-l, ivided inte l is reduced :ind ythe liireziking down lthe tiene, one of wliirffh has.; Hiya-Hyg edge the plates is 'prevented. tively large radius.

Anothei tui-mei condenser in which my. 3. '1i:condenserhavingies invention muy be e'ujilimlied .is shown in llig".l ntitsend into portions which 3, in which4 the dielmtlrie divided yfor ,from one. mutiger faire. entire length intoluwi 'oil hiiiiinuticns md fl- ,A condenek e; the leniinie lire lient iigzmit,y .tei/twist?, l:it the divided :it the D: edge, to Ireduce lhe rvupueitnv.` :md *to* lezi.e portions sm-)grain sin nir gap. orureeess `lug-'tween tlieportions :1 smeelietween t...ni. l of the end of the 'lieleetrieA Simply for y 5,v 1L`ecnclensez Comprising; convenieneelhe .dielectric is shown A:1s `didivided :it u point mf ,Qfr'e mi@ portions vided intel .vo layers. although it isolivieus. which :ire separated te leere between themy thfltas mn'iiv luiers :is'i'lesirerl muy be used. a cavity foi' containing. zi materiel with lVhere the dielectrieis luminutedit is prnepropertiesv different 'from dielectric, ticnlly ilruiossiljilelo inuleliucli luyert have wlwypby the Cnpngt of mi( ("dwtpc ig thel sume properties"througl'umt und conse! varied, v I quently :ilong' the su'j't'nce ofthe. different n (3, A Condenser Comprising n plate :md fb layers :i dill'erenee lili potential often :un dielectric projectingl l'ievond the edge of the peurs, which"results in loeul currents 11;"1 plete with its @rejecting.part divided into the surtue ofthev layers freut enougigu i diuerging portions.; Cause losses ind to produce limiting.V in' @it condenser hailing eoperutiug pluies,-

and a laminated dielectric 4between them With the ends of the leminzie diveiging,- beyondthe edges-ef'the plates.

8. A condenser: comprising a dielectric having e recess in the end thereof, and zi 4metallic sheet embedded in said dielectric finto'the medium Surrounding the condenser.

10. A condenser comprising plates and 'an insulated metallic sheet mounted between said plates with its end projecting beyond I5 the edges of said plates.

11. A'coiidenser comprising plates7 :i'dielectric between said plates with' its end piometallic sheet. mounted between and insiilated troni sziid plates with its end projecting into siiid recess.

Iii Witness whereof, I have hereunto set iny liiiiid this 18th day of April, 1910.

*l KARL KUHLMANN. ritnesses i HENRY HASPER, `WoLniiiiAn HAUPT. 

